The present invention relates to an apparatus for determining the skin tolerance to ultra-violet radiation, comprising a source of ultra-violet radiation and a device for measuring the ultra-violet radiation.
When sun bathing in the open or in so-called solariums, devices are used to an increasing extent to determine the bearable radiation dose from a natural or artificial source of radiation in the erythema active region of between 280 and 315 nm. High ultra-violet radiation has various effects which are harmful to health, such as for example aggravation of latent infections, medication allergies, vegetative disturbances, premature ageing of the skin and skin complaints right up to skin cancer, whilst on the other hand radiation in the UV-A range of between 315 and 390 nm may be used for therapeutic purposes. Applicant's U.S. Pat. application Ser. No. 440,579, filed Feb. 7, 1974 now U.S. Pat. No. 3,917,948 discloses an arrangement for measuring the UV radiation, in which the effect of different proportions of radiation in the UV-B and UV-A regions on human skin are taken into account. The known device has a calibrated measuring cell which feeds an indicating instrument having three measuring regions and is so formed that it not only distinguishes the type of radiation source used, i.e. natural or artificial radiation, but also enables determining of the sensitivity of the skin of the persons to be irradiated. Therefore the known arrangement may be used to ascertain the erythema swelling time of persons of different sensitivity during treatment with natural and artificial UV radiation. This, however, requires complex calculations or reference to a table in order to be able to determine from the measuring value containing the instant intensity on the indicating instrument the radiation dose for a skin type A and a skin type B.
The use of such a device with which the UV-A region can be measured also presupposes specialist knowledge and requires calculations or checking of predetermined values from extensive tables, especially, however, knowledge concerning the given type of skin.
The object of the invention consists in that, by clinically ascertaining average values of energy supply of the UV radiation for each type of skin which produces an erythema to provide a sunbather, a visitor to a solarium or a doctor giving treatment a means of ascertaining the type of skin taking into account the normal skin condition of individuals.
The technical problem underlying the object of the invention is to produce a simple and cheap arrangement by means of which, using any available UV radiation source and a measuring device, at least an erythema may be produced on the skin.